Air-brake



(No Model.)

J. D. P. SGHBNGK.

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J. D. P. SCHENCK.

2 Sheets-Sheet 2.

AIR BRAKE-f Patented Dec. 18, 1894.

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i UNITED STATES 'PATENT OFFICE.

A-l R-BRAKE'.

SPECIFICATION fermingpert of Letters retest No. 531,137, dated December 18,1894.

Ippiieetion mea Meren 12, 1894. serrare. 503,226. (No merel.)

To all whom t may concern.-

Be it known that I, JOHN D. P. SOHENCK, a

brakes according to the speed of the train,

such regulation being eected through the medium of a governor driven from one of the axles of the locomotive, or of a car of the train. Such a device is described in my pending application, Serial No. 480,256, led July 12, 1893,

but with, the device as illustrated in that ap-r plication only two pressures are available, namely, the maximum pressure for high speed above a certain number of miles per hour and a minimum pressure for all speeds below that; The object of this invention is to provide in# termediate brake pressures suited to Various rates of speed.

The invention will be fully described hereinafter and its novel features carefully de! fined in the claims. In its generalY construction the braking mechanism employed is, or may be, the same as that described inmy saidapplica'tion, and in the accompanying drawings I have illus-v trated the application of my improvements to mechanism similar totliat describedin the said application. p, i

In the before mentionedV accompanying drawings-Figure 1 is a somewhat ,diagrammatic view of aportion o'f`a locomotive provided with a braking'mechanism adapted vto my present invention, and Fig. l is a somewhat diagrammatic sectional view of the brak-v ing mechanism onone of the cars'of the train. Fig. 2 is an enlarged sectional view of the automatic valve employed in this class of brakes. Fig. 3 is a view of the governor which operates 'the pressure-controlling valve, the casing 'of the governor and that of the reducingV valve being'in'section. Fig.4is anenlarged sectional view of the valve controlling the counter pressure, and its chest, showingthe valve in one of its positions; and'Figs'iij, 6 and 7 are fragmentaryviews showing ",B'aid valve in three other positions.'

' equal to that in the reservoir 29.

Before proceeding to describe the improvements embodied in and claimed in this application,I will briefly describe ythe braking mechanism as to its general features, premising, however, that this general construction is set forth and claimed in my said pending application.

vReferring to Fig.r1, l is the locomotive, 2

is one of the axles thereof, and 3 is a wheel onjsaid axle. 4 is the main reservoir for compressed air, in which compressed air will be stored by the usual means through a pipe, `5. The compressed air is led by a pipe, 6, to the engineers valve, 7, which valve may be of `the usual kind. A pipe, 8, connects the en- .gineers valve 7, with the train-pipe, 9, through `the casing, l0, of an automatic piston valve,

10a. This valve is seen in Fig. 2, which shows it and its casing in longitudinal mid section. When the engineer admits air from the reservoir 4, to the train-pipe 9, theair enters the casing 10, from piper8,`at what I call the front lend thereof andforces the piston-valve, 10,- `back to the position seen in Fig. 2, thus opening .communicationV between the pipe 8, and

thev train-,pipe 9. The compressed air then lflows to the brake-cylinder under the car.

"The brake apparatus under the car is illustrated in Fig. la, andfconsists of a cylinder,

`28, a piston, 28X, therein, coupled in the usual way to the brake-lever, anda supplementary air-reservoir, 29, connected by a pipe, 29X,

with the cylinder 28,behind the piston. The train-pipe 9, is connected with the cylinder 28, in front of the piston by a branch 9X, and

ing the tension in front of ythe piston, the

pressure of the air behind fthe piston acts to drive the latter forward and set the brakes with a pressure which may be substantially apparatus is not herein claimed, but is merely employed for illustration.

This brake In order to reduce the brake pressure automatically for low speeds, means were em ployed by which, when the train was running at a speed below a certain rate and the engineer opened the train-pipe to the atmosphere for setting the brakes, a counter pressure or back pressure was put on the brake piston 28X. Thus if the tension in the reservoir 29, was seventy pounds and the counter pressure in the train pipe was thirty-tive pounds, the braking pressure would be about thirtytive pounds. The means for accomplishing this is illustrated in my pending application before mentioned and is also illustrated herein in connection with my improvements.

Over the axle 2, is mounted a casing 14, in which is a centrifugal governor, 15, driven from the axle through the medium of gearwheels, 16, one on the axle and the other on the governor spindle. This spindle has bearings in the casing 14. In the casing 14, is mounted a valve-chest, 17, in which plays a slide valve, 18, the stem, 19, of said valve being connected with the governor in such a manner that when the governor balls iiy out the valve 18, will, in the arrangement here shown, be moved upward over its seat.

The valve-chest 17, is connected with the compressed air reservoir 4, by a pipe 20, in which is the casin g 21, of a pressure-reducing valve 21", so that the air from the reservoir, which may be at a tension of seventy pounds, will be reduced to say thirtyfive pounds when it reaches the valve chest 17. The valve 18 controls a port 22, from which a pipe 23 leads to the casing 10 of the automatic valve (Figs. 1 and 2) and enters the same at the end opposite to pipe 8. Consequently, when the train is stopped, or is running at a low rate of speed, the valve 18 uncovers the port 22 and permits air from the valve-chest, at a reduced pressure, to enter the casingof the automatic valve 10, behind the latter and exert thereon a counter pressure, so that if, under these conditions, the engineer sets the brakes by opening pipe 8, to the atmosphere, the pressure in front of valve 10, will `be relieved and the pressure behind it will force it forward so as to cut olf communication between the train pipe 9 and pipe 8, and open communication between the train-pipe and the pipe 23. The pressure behind the brakepiston 28x (Fig. 1) tending to set the brakes,

will then be about seventy pounds, while the counter pressure in front of said piston will be about thirty-five pounds, the difference (thirty-five pounds) being about the actual enough to close the port 22 to the chest and open it to a relief port 24 in the valve seat.;

(See Fig. 4.) This port 24 being open to the;

atmosphere relieves the counter pressure on,` the automatic valve 10' and permits the en-j gineer to put the full pressure on the brakes.

All ofthe above is shown in my former ap plication, and it will be seen that it provides for but one reduction in the brake pressure.

My present invention provides for any desired number of such variations proportioned to as many different rates of speed. The means for accomplishing this will now be described.

Arranged below the relief port 24, are similar relief ports, 25 and 26, which are closed by spring valves, 25X and 26X, respectively. The tension of the spring back of the valve 25x will be less than that back of the valve 26".

The operation of the mechanism described is as follows: When the train is stationary the `slide valve 18 will be in the position seen in Fig. 4, and the air in the valve-chest 17, which we will assume to have atension of thirty-tive pounds, will have free access to the casing of the automatic uvalve 10 by way of the open port 22 and the pipe23. When the train is set yin motion the valve 18 will slowly rise as the speed increases, but until it rises to the position seen in Fig. 5 there will be a counter pressure on the automatic valve 10a equal to thirty-five pounds, and should the engineer set the brakes he will only be able to apply a braking pressure equal to the difference between this counter pressure and that in' the train pipe 9. When the valve 18 shall have risen to the position seen in Fig. 5, the valve will have closed the port 22 to the interior of the valve-chest 17 and opened said port through the medium of a `port passage 27 in the valve, to the relief port 26. The valve 2G", controlling this port, 'is a reducing valve and as soon as the port 26 is opened to the port 22, the counter pressure behind the automatic valve 10 will be reduced from thirtyfive pounds to say twentytive pounds. This will, of course, increase the available braking pressure ten pounds. As the speed of the train continues to increase the valve 18 will continue to rise until the relief port 25is opened to the port 22. This position of the valve 18 is seen in Fig. 6. As the valve 25X at this relief port isset to reduce the counter pressure to a stillgreater extent, say to fifteen pounds, it will be obvious that at this rate of speed the available braking pressure will be again increased ten pounds, making it about fifty-five pounds. As the speed increases and approaches more nearly to the maximum, the valve 18 will rise to the position seen in Fig. 7, wherein the port 22 is open to the relief port 24. As this port has no reducing valve, it will be obvious that all of the counter pressure will now be removed and the eective braking pressure will be equivalent, substantially, to the full pressure in the reservoir 29.

There may, of course, be more than two re yducing relief ports, but the two shown herein `fully illustrate the principle and construction.

I do not limit myself to the specic mechaniing materially from my invention. For ex- IIO the valve. It is only necessary that the governor shall impart the proper extentof movement to the valve and the means for accomplishing this result are within the scope of any skilled machinist.

Having thus described my invention, I claiml. In an air-brake for cars wherein means are employed for putting a counter pressure on the brake-piston at low rates of speed, the combination with the casing 10 of the automatic valve open at one end to the engineers valve, at the other end to a source of compressed air under low tension, and at the side with the train-pipe, the said train-pipe, and the valve 10 in said casing, of a valve adapted to control the admission of air under 10W tension behind the valve 10"', and to openthe said casing in succession to a series of relief' ports, whereby the tension of the counter pressure is regulated, and a governor driven from the axle ofthe train and operating said valve, as set forth.

2. In an air-brake for railway cars, the combination with the automaticvalve controlling the admission of air to the train-pipe when thebrakesare set, to provide a counter pressure of less tension than the main pressure, and the casing of saidvalve, of a valve-chest, open to a source of air at low tension, said chest having a port 22, open to the casing of the automatic valve and back of the latter, and a series of relief ports, some of which are controlled by pressure-reducing valves, a valve 18 in said chest adapted to open the reliefports in succession to the port 22, and a governor driven from oneof the axles'of the train and operating the valve 18, whereby the position of said valve is governed by thespeed at which the train is moving, as set forth.

3. In an air-brake for railway cars, the combinationwith the main air-reservoir, a pipe connecting said reservoir with the train-pipe,

v the automatic valve and engineers valve co'ntrolling the flow of air to the train-pipe, the said train-pipe, and a governor driven from an axle of the locomotive or train, of a valvechest open to air under a tension less than that in the main reservoir, said chest having Va port 22, open to the casing of the automatic valve and backk of said valve, a relief port 24, open to the atmosphere and a relief port or ports controlled by spring valves which resist the outflow of air thereat, and a valve operated by the ygovernor'and adapted to open the port 22 to one or the other of the said relief ports, according to the speed at which the train is moving, as set forth.

4. In an air-brake for cars wherein means are employed for automatically regulating the effective braking pressure in accordance with the speed of the train, the combination with a main compressed air-reservoir, an engineers-valve, a train-pipe, an automatic cut-off valve between the engineers valve and the train-pipe on the car, means for supplying air at a tension below the maximum tmlsion behind said automatic valve for actuating it to cut o the train-pipe from the engineers valve andopening the train-pipe to the reduced air-pressure, and a governor driven from one of the axles of the train, of means controlled by said governor for effecting a graduated reduction of the tension of the air behind said automatic cut-olf valve at intervals Yas the speed of the train increases, substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

- JOHN D. P. SCHENCK. Witnesses:

CHARLES A. WINTER, EDWARD WINTER. 

